So I have decided to just take the time to properly list the details on EXACTLY how to properly remove your themes because I am tired of reading posts day after day about people having problems with either installing or removing their homebrew themes.
If you have a way of doing this other than what I have mentioned following please feel free to share so that others may share your knowledge.Please stop posting thread after thread about questions related to this!!!

Installing with webOS Quick Install (WOSQI)
There are 2 ways of installing themes via wosqi and this assumes that you already have wosqi on your computer and properly setup. If you do not please follow the instructions on this threadWebOS Quick Install

Scroll down to the large button "DOWNLOAD" on PreThemer Gallery. A new window will open and you will have the option to download a zip or a ipk. Download the .ipk file.

Click on the link located in this section

You will be downloading an .ipk file.

Remember where you downloaded the file

Now open WebOS Quick Installer

In the main window select the large plus sign.

A browser window opens up. Hope you remembered where you downloaded the .ipk

Choose the .ipk file and press "Select"

Now that the file has been added to the queue window and your phone is connected via the usb cable. Press the large "Install!" button on the bottom of the window.

A popup window appears saying "Please wait..." So please wait and let wosqi do its thing.

The window will disappear and the phone will automatically restart. and YOU ARE DONE!!!

Uninstalling with WebOS Quick Install
This should ONLY be used with themes that are installed using wosqi. Do not use this for themes installed via Preware. This removes both zip files and .ipk files.

DO NOT INSTALL NEW THEMES OVER OTHER ONES. This will cause your phone to install themes over each other and files will be permanently changed. Some files may be changed and will not be changed to the default using this method. You wil have to us WebOS Doctor otherwise. And this sucks.

Follow the above directions to get back into wosqi and to the Themer area.

The "Theme Settings" window will now give you an option to "Revert to Default" Choose this option.

Again the "Changing Theme" window will open. Let the program do its thing and do not touch/disconnect the phone.

Once it has finished a "Theme removed" window will appear. Press "Ok" and let the phone restart.

Once it has restarted the theme will be completely removed and you are set.

Preware Theming
Preware is a great application that has been contributed to the homebrew community and has made theming very simple to do for any user. This has also created problems for users that are unaware of some of the problems when it comes to theming. Please follow these instructions in order to put Preware on your phoneDownload Instructions for Preware

Installing themes with Preware
With Preware there is only one way to install these themes.DO NOT IGNORE THE INSTRUCTIONS ABOVE. READ FULLY AND FOLLOW THE INSTRUCTIONS TO THE "T."

Once you have Preware on your phone update the feeds to get the latest themes and packages in your listing.

Select "Available Themes" from the menu.

Select the theme you would like to install.

A preview (if available), description, and other creator information pulls up on the screen along with a button on the bottom of the screen called "Install"

Click "Install"

The screen will now go to an activity timer with the text "Downloading/Installing."

Wait for it to do it's thing.

Another prompt screen will say that the theme requires a script to be executed. It will give you three options "Ok," "View," and "Cancel." Select "Ok" if you would like to install the theme.

The screen will again go to the activity timer. Again wait a bit. This will take different amounts of time depending on the complexity of the theme.

Now another prompt screen will pop up letting you know that the theme is installed and that "Luna Restart Is Required." Click "Ok."

The phone will restart and when it comes back to the Home screen your theme will be installed. YOU ARE DONE!!!

Uninstalling with Preware
This can only be done with themes that are installed with Preware.DO NOT TRY TO UNINSTALL A THEME WITH PREWARE THAT WAS INSTALLED VIA OTHER MEANS.

Open up the Preware application.

Once the main menu appears, select "Installed Packages."

Another menu will appear with anything installed on your phone. Select "Theme."

You will now see the name of the theme that you have installed. Select this theme.

The preview/description page will appear for the theme this time with a "Remove" button located on the bottom middle.

Select "Remove."

The screen will now go to an activity timer with the text "Removing."

Wait for it to do it's thing.

Another prompt screen will say that the theme requires a script to be executed. It will give you three options "Ok," "View," and "Cancel." Select "Ok" if you would like to remove the theme.

The screen will again go to the activity timer. Again wait a bit. This will take different amounts of time depending on the complexity of the theme.

Now another prompt screen will pop up letting you know that the theme is removed and that "Luna Restart Is Required." Click "Ok."

The phone will restart and when it comes back to the Home screen your theme will be removed. YOU ARE DONE!!!

Can you install themes with patches already in place or should I uninstall patches before installing a theme? I am worried about the Luna Restart messing with my patches, specifically the virtual keyboard. Thanks for you help.

This is not a straight yes or no answer. It depends entirely on the theme. Some themes make changes that could screw with patches while others do not. Personally if it's a theme you havent used before I would probably remove the patches just because you don't know what their theme does. Or you could email the developer and ask them.

So, overall, I would say be careful. Ask the developer if they made any changes to the source code that would effect patches and if you don't email them then just remove all the patches first and then switch themes.

sam_inc, it appears that you unzipped the theme instead of loading it into webOS QI as a zipped folder. The instructions above explicitly state this. Go back to QI, select load theme, then find and select the zipped folder. Read the remainder of the instructions carefully and follow them exactly.

ahhhhhh YES!!!!! well done cas_esq....he is trying to install the xml file and not the zip folder itself. well done. and yes...sam just try following the instructions exactly how I have posted up above. Thanks to cas and sam good luck and pm me if you need nething.

I accidently installed two themes at the same time not knowing what i was doing. I promptly uninstalled it and installed a completely different theme but now everytime i uninstall a theme, remnants of the first two themes remain how do I completely get rid of the themes so my pre can look normal again ?

ok im using preware now...how do u remove the theme i went to patches but i cant find where they say to remove it. and im tryign to install a new theme but it says erroe

As you have been told on multiple occasions, providing more information will result in a quicker, more constructive answer. If you are attempting to uninstall the theme through Preware, I will assume you installed it using Preware. (You wouldn't try to uninstall the theme using Preware if you installed it using QI because the instructions above explicitly tell you not to do that. Because you have listened to all of the advice you received in your multiple previous threads and heeded the admonishment of the moderator who closed your previous threads, I know that you have carefully read the information presented in this site, these forums, and this very thread. So, here goes . . . .)

In Preware, go to Installed Packages, Theme, choose the theme, and then press Remove. Of course, if you need to uninstall the theme using QI, you will read the instructions above. If you get lost, you can then post a message giving details so that someone can quickly and efficiently help you. (I'm not going to go through what those details ought to look like; I and others have provided that info in your other threads.)

no my phone didnt restart the theme just appreaded and i was tryin to remove but i dnt see no theme in the install packages

Then you will need to provide a detailed description of how you installed the theme. The installation of the theme should have resulted in a restart of your phone. In your next post, include the name of the theme and the steps you took to install it. Then include exactly what you've done to attempt to uninstall it. That will make it easier for someone to help you.

ok i went to theme and i installed "epic black" i click on install and it show me "ok" cancel" and "view" I click on view because i wanted to see how it look. then it was telling me to click on ok and it appreaded. on my phone..my phone did not restart

i have it here right now. Its telling me to install but i already have this theme already it should say remove